A summary of the first half of the course

What is common to dualists is the view that some mental properties are properties no entirely physical thing could have. According to a substance dualist, certain mental properties that people have are properties that nothing that had any physical properties could have. Thus there are two different sorts of thing that do not overlap: things that have mental properties, and physical things. A property dualist holds a weaker view: even if a given mental property is compatible with physical properties, it is quite separate from the physical properties of thing things that have it: a thing’s physical nature doesn’t determine whether it has that mental property. An influential argument for substance dualism is the argument from the possibility of disembodiment, which we considered in the second lecture. (The handout from that class is on the web, so I won’t discuss it further here.) You could deny dualism even if you believed in ghosts and all kinds of mental life having nothing to do with the physical world. But people are typically motivated to deny dualism by their belief in materialism, also known as physicalism. Materialism says that there is nothing more to the nature of the world than its physical nature— or at least, nothing that is relevant to the philosophy of mind. We can capture this claim as a claim about supervenience: any possible world that is a minimal-physical duplicate of the actual world is just like the actual world in all respects—or at least, in all mental respects. There are many arguments for materialism and against dualism. One of them is the causal argument, discussed by BMJ (pp. 6–13). Another is the problem of other minds: it is suggested that if mental properties were independent of physical properties, we could not be justified (as we in fact are) in drawing conclusions about a person’s mental life on the basis of evidence about the physical state of their body. There is also a widespread view that materialism is the natural or default position, so that the burden of proof is on the opponents of materialism to show that it is false. Behaviourism, the Identity Theory, and Functionalism are all compatible with materialism, and typically supported by materialists.